Stimulable phosphor and radiation image conversion panel by use thereof

Abstract

A method for preparing a stimulable phosphor is disclosed, comprising forming a stimulable phosphor and coating the formed stimulable phosphor with a metal oxide and a silane coupling agent, or a metal oxide and a metal alkoxide. Another method is also disclosed, comprising forming a stimulable phosphor precursor, calcining the formed precursor in the presence of a metal oxide or metal alkoxide, and coating the calcined precursor with a silane coupling agent or metal alkoxide. Further disclosed is a preparation method of a radiation image conversion panel containing the stimulable phosphor.

What is claimed is:  
     
       1. A method for preparing a stimulable phosphor comprising the steps of: 
       (1) forming a stimulable phosphor and  
       (2) coating the formed stimulable phosphor with a metal oxide and a silane coupling agent, or metal oxide particles and a metal alkoxide.  
     
     
       2. The method of claim  1 , wherein said silane coupling agent contains a mercapto group. 
     
     
       3. The method of claim  1 , wherein said silane coupling agent contains a vinyl group. 
     
     
       4. The method of claim  1 , wherein in step (2), the formed stimulable phosphor is coated with metal oxide particles in an amount of 0.05 to 10% by weight, based on the stimulable phosphor, and a silane coupling agent or metal alkoxide in an amount of 0.1 to 5% by weight, based on the stimulable phosphor. 
     
     
       5. The method of claim  1 , wherein said metal oxide particles have been subjected to a hydrophobicity-enhancing treatment. 
     
     
       6. The method of claim  1 , wherein said metal oxide particles are particles of metal oxides selected from the group consisting of silica, alumina and titanium oxide. 
     
     
       7. The method of claim  1 , wherein said stimulable phosphor comprises Ba, F, XA, and Ln, in which XA is at least one selected from the group consisting of F, Cl, Br, I, At, Yb and No; and Ln is at lest one selected from the group consisting of Ce, Pr, Sm, Eu, Gd, Tb, Tm, Dy, Ho, Nd, Er and Yb. 
     
     
       8. The method of claim  7 , wherein said stimulable phosphor is represented by formula (1): 
       
         
           (Ba 1−x M 1 )FX: y M 2 , z Ln  
         
       
       wherein M1 represents a metal selected from the group consisting of Mg, Ca, Sr, Zn and Cd; M 2  represents an alkali metal selected from the group consisting of Li, Na, K, Rb and Cs; X represents a halogen selected from the group consisting of Cl, Br and I; and Ln represents a rare earth element selected from the group consisting of Ce, Pr, Sm, Eu, Gd, Tb, Tm, Dy, Ho, Nd, Er and Yb; and wherein x, y and z each represent 0≦x≦0.6, 0≦y≦0.05, 0≦z≦0.2. 
     
     
       9. A method for preparing a stimulable phosphor comprising the steps of: 
       (1) forming a stimulable phosphor precursor,  
       (2) calcining the formed precursor in the presence of first metal oxide particles, and  
       (3) coating the calcined precursor with a silane coupling agent or metal alkoxide.  
     
     
       10. The method of claim  9 , wherein said silane coupling agent contains a mercapto group. 
     
     
       11. The method of claim  9 , wherein said silane coupling agent contains a vinyl group. 
     
     
       12. The method of claim  9 , wherein in step (2), the formed stimulable phosphor is coated with a silane coupling agent or metal alkoxide in an amount of 0.1 to 5% by weight, based on the stimulable phosphor. 
     
     
       13. The method of claim  9 , wherein said metal oxide particles is one which has been subjected to a hydrophobicity-enhancing treatment. 
     
     
       14. The method of claim  9 , wherein said first metal oxide is selected from the group consisting of silica, alumina and titanium oxide. 
     
     
       15. The method of claim  9 , wherein the step (3) is coating the calcined precursor with a silane coupling agent and a second metal oxide, or a metal alkoxide and a second metal oxide. 
     
     
       16. The method of claim  15 , wherein said first metal oxide is alumina, said second metal oxide being silica. 
     
     
       17. The method of claim  9 , wherein said stimulable phosphor comprises Ba, F, XA, and Ln, in which XA is at least one selected from the group consisting of F, Cl, Br, I, At, Yb and No; and Ln is at lest one selected from the group consisting of Ce, Pr, Sm, Eu, Gd, Tb, Tm, Dy, Ho, Nd, Er and Yb. 
     
     
       18. The method of claim  17 , wherein said stimulable phosphor is represented by formula (1): 
       
         
           (Ba 1−x M 1 )FX: y M 2 , z Ln  
         
       
       wherein M 1  represents a metal selected from the group consisting of Mg, Ca, Sr, Zn and Cd; M 2  represents an alkali metal selected from the group consisting of Li, Na, K, Rb and Cs; X represents a halogen selected from the group consisting of Cl, Br and I; and Ln represents a rare earth element selected from the group consisting of Ce, Pr, Sm, Eu, Gd, Tb, Tm, Dy, Ho, Nd, Er and Yb. 
     
     
       19. A method for preparing a stimulable phosphor comprising the steps of: 
       (1) forming a stimulable phosphor precursor,  
       (2) calcining the formed precursor in the presence of a metal alkoxide, and  
       (3) coating the calcined precursor with a silane coupling agent and metal oxide, or metal alkoxide and metal oxide.  
     
     
       20. The method of claim  19 , wherein after step (1) and prior to step (2), the method further comprising: 
       (1A) allowing said metal alkoxide to adhere to the formed precursor,  
       and step (2) is calcining the metal alkoxide-adhered precursor. 
     
     
       21. The method of claim  20 , wherein step (1A) is immersing the formed precursor in a solution containing said metal alkoxide. 
     
     
       22. A method for preparing a stimulable phosphor comprising the steps of: 
       (1) forming a stimulable phosphor precursor,  
       (2) calcining the formed precursor in the presence of a first metal alkoxide and a first metal oxide particle, and  
       (3) coating the calcined precursor with a silane coupling agent or a second metal alkoxide.  
     
     
       23. The method of claim  22 , wherein step (3) is coating the calcined precursor with a silane coupling agent and second metal oxide particles, or a second metal alkoxide and a second metal oxide. 
     
     
       24. The method of claim  22 , wherein after step (1) and prior to step (2), the method further comprising: 
       (1A) allowing said first metal alkoxide and first metal oxide to adhere to the formed precursor,  
       and step (2) is calcining the first metal alkoxide and first metal oxide-adhered precursor. 
     
     
       25. The method of claim  24 , wherein step (1A) is immersing the formed precursor in a solution containing said first metal alkoxide and first metal oxide. 
     
     
       26. A method for preparing a radiation image conversion panel comprising the step of: 
       forming a phosphor layer containing a stimulable phosphor prepared according to the method as claimed in claim  1 .  
     
     
       27. The method of claim  26 , wherein the method further comprising the step of: 
       forming a protective layer on the phosphor layer.  
     
     
       28. A method for preparing a radiation image conversion panel comprising the step of: 
       forming a phosphor layer containing a stimulable phosphor prepared according to the method as claimed in claim  9 .  
     
     
       29. The method of claim  28 , wherein the method further comprising the step of: 
       forming a protective layer on the phosphor layer.  
     
     
       30. A method for preparing a radiation image conversion panel comprising the step of: 
       forming a phosphor layer containing a stimulable phosphor prepared according to the method as claimed in claim  19 .  
     
     
       31. The method of claim  30 , wherein the method further comprising the step of: 
       forming a protective layer on the phosphor layer.  
     
     
       32. A method for preparing a radiation image conversion panel comprising the step of: 
       forming a phosphor layer containing a stimulable phosphor prepared according to the method as claimed in claim  22 .  
     
     
       33. The method of claim  28 , wherein the method further comprising the step of: 
       forming a protective layer on the phosphor layer.